This invention relates to an automatic squeezee pressing device for pressing squeezees used for cleaning window panes against a window pane with a constant pressing force so that window panes can be cleaned without leaving an uncleaned portion notwithstanding an error in mounting window panes to a building or existence of a curved portion in a window pane.
As high-storied buildings increase, the number of windows formed in these buildings also increases. For maintaining window panes of these windows clean, a regular window pane cleaning work becomes necessary.
A conventional window pane cleaning work is carried out manually by an operator who splashes water over a window pane from a moving scaffold hung from a roof of a building, wipes dust off the window pane by a squeezee and collects dust with soiled water. Such manual cleaning work is inefficient and besides is dangerous.
A device has been developed to automate the window pane cleaning work. According to this prior art device, as shown in FIG. 3, a pair of vertically arranged squeezees 2 and 3 are mounted on a cleaning unit 1 which is hung from a roof of a building and is adapted to move up and down and a spray nozzle 4 is provided between these squeezees 2 and 3. Water is sprayed over a window pane W by the spray nozzle 4 while the cleaning unit 1 is moved down and dust is removed by the upper squeezee 2 and collected into a soiled water tank (not shown) by the lower squeezee 3.
For performing a satisfactory cleaning work by this prior art window pane cleaning device, it is necessary to keep pressing at least the upper squeezee 2 among the pair of squeezees 2 and 3 to the surface of the window pane W with a constant force. For this purpose the, length of projection of the squeezees 2 and 3 from the cleaning unit 1 is adjusted, before starting of the cleaning work, by changing positions at which these squeezees 2 and 3 are fixed to the cleaning unit 1.
The interval between the surface of the window pane W and the cleaning unit 1, however, is not constant because there are variations, occurring due to an error in the mounting work, in a position at which guide members are mounted along the window for guiding the cleaning unit 1 in moving up and down along the window and also in a position at which the window pane is mounted in the window. Pressing force of the squeezees 2 and 3 therefore varies due to such variation in the interval between the surface of the window pane W and the cleaning unit 1.
For this reason, the position of the upper squeezee 2 with respect to the window pane W tends to shift from an optimum position shown in FIG. 4a to a position shown in FIG. 4b which is too spaced away from the window pane W or to a position shown in FIG. 4c which is too close to the window pane W. This causes the problem that an unwiped portion is left on the window pane W after the cleaning work (in the case of FIG. 4b) or that resistance to the squeezees increases or scars are produced on the window pane W (in the case of FIG. 4c).
In some buildings in which window panes W continue in the horizontal direction, the cleaning work must be performed by moving the cleaning unit 1 horizontally. In this case also, there occurs an error in mounting of window panes and, besides, a curved window pane is sometimes employed at a corner of the building. The interval between the squeezee 2 and the surface of the window pane W must vary at the corner portion of the window pane W as shown in FIG. 4d with a result that an unwiped portion is left on the curved window pane W or, conversely, resistance to the squeezee 2 increases.
It is, therefore, an object of the invention to provide an automatic squeezee pressing device capable of pressing squeezees with an optimum constant force over the entire width of a window pane and thereby achieving an excellent window pane cleaning work.